Phenolic substituted propionitrile



United States Patent PVHENOLIC SUBSTITUTED PROPIONITRILE Thomas H.Coflield, Farmington, Mich., assignor to Ethyl Corporation, New York,N.Y., a corporation of Delaware No Drawing. Application December 18,1957 Serial No. 703,478

3 Claims. (CI. 44-75) methyl phenol or the like in which the hydrogenatom of the hydroxyl :group is replaced by the metallic atom. Instead,in the novel salts of this invention, the metal atom is probably bondedin resonance hybrid form to the para position of the phenol. These novelcompounds of this invention open up a new field of chemicalreactionsinvolving the para position of the original phenol and consequently leadto the formation of novel and eminently useful chemical compounds. willrelate to a detailed consideration of the novel metallic salts of thisinvention, the preparation thereof, the uses thereof and the novelproducts which can be readily prepared therefrom.

An object of this invention is to provide novel and useful chemicalcompounds. Another object is to provide' novel and useful metal salts ofcertain 2,6dialkyl phenols, which salts are eminently useful inconducting novel chemical reactions. Another object is to provideprocesses of preparing the novel salts of this invention. Another objectis to provide novel and useful chemical reactions involving the novelmetallic salts of this invention. A further object is to provide noveland useful chemical compounds which are prepared by novel reactionsinvolving use of the metallic salts of this invention as chemicalintermediates. A still further object is to provide improvedcompositions of matter containing the various novel compounds of thisinvention. Other important objects of this invention will be apparentfrom the following description.

According to this invention the above and other objects are accomplishedby providing as a new composition of matter a metal salt of a2,6-dialkyl phenol, saidphenol having the formula: J

tert-butyl-G-tert-amyl phenol, 2,6-di-(1,1,2,2-tetramethy1- The ensuingdescription 2,903,346 Patented Sept. 8, 1959 2 propyl) phenol,2,6-di-(l-methyl-l-ethyl-amyl) phenol and the like.

The metals Which form the phenol salts of this invention are metalswhich are capable of forming ionic salts with anions of strong acidssuch as sulfate, nitrate and chloride. Thus, the metallic portion of thenovel phenol salts of this invention can be a metal from groups IIB,IIIA, IVA, IVB, VA, VIIB, and VHI. Examples of such metals are: zinc,cadmium, aluminum, tin, lead, titanium, antimony, manganese and iron.However, itis preferable to prepare the novel metallic salts ofthisinvention from metals whose hydroxides are strong bases. Of suchmetals the alkali metalslithium, sodium, potassium, rubidium andcesium-and the alkaline earth metals-magnesium, calcium, strontium andbarium-are preferred because the phenolic salts of such metals areeasily prepared and are particularly valuable as chemical intermediates.From the standpoints of favorableeconomics and useful reactivity thesodium salts of the above described phenols are most advantageous andare particularly preferred.

The novel metallic salts of.2,6-dialkyl phenols as above described arenot easily susceptible of pictorial representation inasmuch as they areevidently the result of resonance hybrid forms. However, these salts actas if the metallic constituent is substituted in the para position ofthe phenol. Thus, the metallic salts of this invention may berepresented by the following general formula:

wherein R and R are tertiary alkyl groups, M is a metal as abovedescribed and n is an integer from 1 to 2. Accordingly, the above metalsalts of this invention consist of metallic cation and one or two2,6-di-tert-alkyl cyclohexadienone carbanions. Inthe case of thepolyvalent metals such as magnesium, tin, zinc, cadmium, aluminum or thelike, the metal salts of this invention comprise three chemicalentities, namely, the metallic cation, one or more of the abovecarbanions and sufficient halide atoms to satisfy the remainingvalencies of the metallic cation. Such metallic salts may be representedbythe following general formula:

H a wherein R and R are tertiary alkyl radicals, M is a polyvalentmetal, X is a halogen low-fluorine, chlorine, bromine and iodine-4!. isan integer from 2 to 4 and a and b are integers from 1 to 3 the total,of a and b being equal to n.

An unusual feature of the compounds of this invention depicted above isthat the configuration of the 2,6-di-tertalkyl cyclohexadienone ions issuch that there is a high electron density concentrated at the end ofthe carbanion opposite tothe oxygen atom. Therefore, chemical reactionsof these salts are focused upon this para position leading to novel anduseful chemical compounds.

The above metal salts of phenols can be preformed that is, prepared andisolated-and used in chemical reactions, or they can be prepared insitu. In'this latter case the novel metallic salts are prepared andsubjected to further chemical reaction without isolation.

A reaction vessel was equipped with a reflux condenser and stirringmeans. In this vessel were placed 100 parts anhydrous methanol and 2.3parts of sodium. When the reaction had subsided 20.7 parts of2,6-di-tert-butyl phenol were added to the reaction mixture and thereflux condenser replaced by a vacuum take-off. A vacuum was applied tothe system and the alcohol evaporated while the flask contents werestirred and heated to 80 C. As the evaporation proceeded the contentsbecame viscous and finally solidified. Continued rapid stirring andheating gave the product as a fine light green powder. The last tracesof methanol were removed by gently flaming the reaction vessel with aBunsen burner. The resulting sodium salt of 2,6-di-tert-butylphenol canbe stored for long periods of time when maintained under a dry inert gassuch as nitrogen. This salt is readily hydrolyzed by water to form2,6-di-tert-butylphenol and sodium hydroxide.

Example 11 The procedure of Example I is repeated in identical mannerwith the exception that after the addition of the2,6-di-tert-butylphenol is complete, 300 parts of toluene are added andthe methanol removed as a methanoltolueue azeotrope leaving a slurry ofthe sodium salt of 2,6-di-tert-butylphenol in toluene.

Example III To a reaction vessel equipped with a condenser, stirringmeans, reagent introducing means and a nitrogen inlet was added 6.1parts of magnesium metal, 35.5 parts of methyl iodide and 140 parts ofanyhydrous diethyl ether. To the resulting solution of methyl magnesiumiodide was added slowly with stirring 51.5 parts of 2,6-di-tert-butylphenol dissolved in 35 parts of anhydrous diethyl ether.Methane was evolved. A grayish white precipitate of the magnesiummonoiodide salt of 2,6-ditert-butylphenol was formed. The anhydrousdiethyl ether is removed from this salt by vacuum evaporation. Theresulting dry salt can be stored under an anhydrous inert gas blanket.

Example IV Example V To the reaction equipment of Example IV containing2.2 parts of methyl lithium in 200 parts of diethyl ether is addedportionwise 20.7 parts of 2,6-di-tert-butylphenol. Methane is liberatedand the lithium salt of 2,6-di-tertbutylphenol formed.

Example VI To the reaction equipment described in Example IV is added200 parts of mixed xylenes, 2.1 parts of calcium hydride and the mixtureheated to reflux. 20.7 parts of 2,6-di-tert-butylphen01 are addedincrementally to the refluxing mixture and heating continued untilhydrogen evolution has ceased. The product of this reaction, the calciumsalt of 2,6-di-tert-butylphenol, contains two 2,6-d-tert-buty1cyclohexadienone carbanions The po- 4 per atom of calcium.This salt is insoluble solid which separates readily from the xylenes.

Example VII To the reaction vessel of Example IV is added 300 parts oftoluene and 4.25 parts of dimethyl zinc. To the resulting solution isadded 23.4 parts of 2,6-di-tert-amyl phenol. Methane gas, which isevolved, is removed from the reaction vessel as formed. The product ofthis reaction is the zinc salt of 2,6-di-tert-amyl phenol which containstwo 2,6-di-tert-amyl cyclohexadienone carbanions per atom of zinc. It isseparated from the toluene by filtration under an inert anhydrousatmosphere.

Example VIII The apparatus of Example IV is charged with 300 parts oftoluene containing 8.5 parts of diethyl cadmium. The mixture is heatedto reflux and 31.8 parts of 2,6-di- (1,1,3,3-tetramethylbutyl) phenolincrementally added. When evolution of ethane has ceased the mixture iscooled and the product obtained by filtration. The cadmium salt of2,6-di-(1,1,3,3-tetramethylbutyl) phenol contains two2,6-di-(l,1,3,3-tetramethylbutyl) cyclohexadienone carbanions per atomof cadmium.

Example IX 24 parts of the sodium salt of 2,6-di-tert-butylphenolsuspended in 200 parts of toluene is prepared according to the procedureof Example I. This suspension is then introduced into the reactionvessel of Example IV. To this suspension is added 9.5 parts of titaniumtetrachloride while maintaining the contents of the vessel under ablanket of inert anhydrous nitrogen gas. The temperature of thereactants is maintained at a temperature below 50 C. The titaniumdichloride salt of 2,6-di-tertbutylphenol is formed.

Example X Dicyclopentadienyl manganese is prepared by the method of E.O. Fischer and R. Jira, Zeitschrift fiir Naturforschung 9B, 618-19(1954). Using the reaction equipment of Example IV 18.5 parts ofdicyclopentadienyl manganese suspended in 200 parts of hexane is reactedwith 20.7 parts of 2,6-di-tert-butylphenol. This phenol is addedportionwise to the suspension which is maintained at reflux temperature.The solvents and the resultant cyclopentadiene are removed by vacuumdistillation to yield the manganese salt of 2,6-di-tertbutylphenol.

Example XI Using the apparatus of Example IV 3.9 parts of sodamide issuspended in parts of octane and 22.0 parts of 2-tert-butyl-6-tert-amylphenol slowly added at reflux temperature. The preparation of the sodiumsalt is complete upon the completion of the evolution of ammonia. Thesodium salt of 2-tert-butyl-6-tert-amyl phenol is then separated fromthe octane by filtration under an inert anhydrous atmosphere ofnitrogen.

The above examples are illustrative of the novel metallic salts of thisinvention and the methods for the preparation thereof. Other modes ofpreparing the compounds of this invention will now be apparent to thoseskilled in the art.

It can be seen from the preceding examples that the novel metallic saltsof this invention can be prepared by a variety of methods. Generallyspeaking, the alkali metal salts of this invention are best prepared byreacting an alkali metal alkoxide with an appropriate 2,6- di-tert-alkylphenol. If desired, recourse may be had to reaction between such phenoland a suspension or dispersion of the alkali metal, an organo alkalimetal compound such as phenyl sodium, amyl sodium, ethyl lithium, methylpotassium or the like, or inorganic alkali metal compounds such as thehydrides or amides. The same general methods are also applicable to thepreparation of the alkaline earth metal salts of this invention. In thecase of the magnesium salts of this invention, the most efiicaciousmethod involves reaction between a standard Grignard reagent and a2,6-di-tert-alkyl phenol. Thus, a facet of this invention is theprovision of a novel process for preparing the novel metallic salts ofthis invention. This process comprises reacting a 2,6-ditert-alkylphenol with a member selected from the class consisting of (1) Grignardreagents, (2) alkaline earth metal hydrides, (3) alkali metals, and (4)compounds having the formula:

wherein M is an alkali metal and R is selected from the group consistingof hydrogen, amide, alkyl and aryl.

To demonstrate the unique and surprising chemical reactions which thenovel metallic salts of this invention undergo comparative experimentswere conducted on the cyanoethylation of the sodium salt of 2,6-dialkylphenols. In one instance, the sodium salt of 2,6-diisopropyl phenol wasreacted with acrylonitrile yielding an oxygen-alkylated product. In thecase of the cyanoethylation of the sodium salt of 2,6-di-tert-butylphenol, a para alkylated product was obtained. This striking diflerencein mode of reaction will be further apparent from the following specificexamples in which all parts and percentages are by weight.

Example XII The sodium salt of 2,6-diisopropyl phenol was made by adding17.8 parts of 2,6-diisopropyl phenol to a solution of 2.3 parts ofsodium in 120 parts of methanol. The methanol was evaporated by applyinga vacuum to the reaction vessel and the last traces removed by heat- Thesodium salt of 2,6-di-tert-butylphenol was prepared by the reaction of2,6-di-tert-butylphenol with sodium methylate and the resultant methanolremoved under Vacuum. To this dry salt was added 47 parts of2,6-di-tert-butylphenol and 106 parts of acrylonitrile. A clear darkgreen solution resulted. This solution was stirred at 50 C. for fourhours, cooled and allowed to stand for 16 hours. The contents of thereactor were thoroughly washed with cold water, and the organic layerwas separated, dried over magnesium sulfate and the solution evaporated.The residue from this evaporation was subjected to fractionalcrystallization from petroleum ether to give white needles melting at111 to 113. The infra-red spectrum showed this material to be[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionitrile. Chemical analysisshowed: carbon, 78.80 percent; hydrogen, 9.78 percent.

It will be readily apparent from Examples XlI and XIII that the modes ofreactions were very different when using a salt of this invention(Example XlII) compared with a metallic salt not of this invention(Example XII). This difierence in mode of reactivity demonstrates thatthe metallic salts of this invention behave during chemical reaction asif the metallic portion thereof were substituted in the position of the2,6-di-tert-alkyl cyclohexadienone carbanion opposite to the carbonylgroup. Thus, the novel salts of this invention are markedly differentfrom the corresponding metallic salts of phenols which do not containtertiary alkyl groups in both positions ortho to the hydroxyl group. Inthese latter salts the metal replaces the hydrogen atom of the hydroxylgroup to form conventional metallic phenoxide salts havingmetal-to-oxygen bonds.

The totally unexpected mode of reactivity of a novel metal salt of thisinvention described in Example XIII is exhibited by the other metalsalts of this invention. For example, by subjecting the alkali metalsalts of 2,6-di-tert-alkyl phenols to cyanoethylating conditions, thecorresponding para-cyanoethylated phenols are obtained.

To still further demonstrate the remarkable properties of the metallicsalts of this invention in making possible reactions involving the parapositions of the starting phenols, comparative experiments wereconducted on benzoylation of difierent phenols. In one case the sodiumsalt of 2,6-diisopropyl phenol was reacted with benzoyl chloride.Benzoylation occurred at the oxygen atom. In the second case, involvinguse of the sodium salt of 2,6-di-tert-butyl phenola compound of thisinventionbenzoylation occurred on the ring opposite to the carbon atomto which is attached the oxygen atom. The striking dissimilarity betweenthese reactions will be further apparent from the following specificexamples wherein all parts and percentages are by weight.

Example XIV In a reaction vessel equipped with a high speed stirrer,reflux condenser, inlet means, thermometer, and nitrogen sweep wereplaced 300 parts of dry dioxane and 2.3 parts of sodium. The contents ofthe vessel were brought to reflux at 101 and the sodium dispersed byrapid stirring under nitrogen. The dispersion was cooled to 60 and 17.5parts of 2,6-diisopropyl phenol in 30 parts of dioxane slowly added overa 0.5 hour period. A slow evolution of hydrogen was noted. The mixturewas heated to and after 20 minutes no further hydrogen evolution wasobserved. The mixture was cooled to 58 and to it was added over a 5minute period 14 parts of benzoyl chloride. The temperature rose to 64and a gelatinous precipitate formed. The mixture was allowed to standfor 16 hours and then filtered to remove inorganic solids. Evaporationtaken up in ether, the ether solution washed with 10 percent aqueoussodium hydroxide, dried over sodium sulfate, and evaporated. Theresultant oil readily crystallized from water-ethanol solution (40:150)to give 18.4 parts of 2,6-diisopropyl phenylbenzoate, M.P. 70-72. Thestructure of this compound was established by means of its infra-redspectrum. Analysis-Calculated for C H O carbon 80.81 percent, hydrogen7.9 percent. Found: carbon 80.9 percent, hydrogen 8.2 percent.

Example XV The sodium salt of 2,6-di-tert-butylphenol was prepared byreacting parts of anhydrous methanol with 5.7 parts of sodium to formsodium methylate which in turn was reacted with 52 parts of2,6-di-tert-butyl phenol. Excess methanol was removed from the reactionvessel by the application of heat. To the dry sodium salt of2,6-ditert-butyl phenol was added 300 parts of dioxane and the resultingslurry heated to 60 C. To this slurry was added portionwise over aperiod of one minute, 33 parts of benzoylchlon'de dissolved in 25 partsof dioxane. A rapid reaction occurred causing the temperature to rise to80 C. The contents of the reaction vessel varied in appearance from agreen to a yellowish color. The temperature was reduced to 25 C. whilestirring. The mixture was then washed with water, ether added, theorganic layer separated and dried over sodium sulfate. Evaporation atreduced pressure gave a brown viscous oil from which was recovered acream colored solid melting from 120 to C. This solid crystallized fromligroin to yield a product having a melting point of 124 to 126 C. Theinfra-red spectrum showed the compound to be 2,6-di-tert-butyl-4-benzoyl phenol. Analysis showed 81.20 percent of carbonand 8.53 percent of hydrogen whereas the empirical formula C H Orequires 81.25 percent of carbon and 8.44 percent of hydrogen.

By referring to Examples XlV and XV it is readily apparent that onceagain the course of the respective reactions was decidedly different.When a metallic salt of 2,6-di-isopropyl phenol was used, benzoylationreaction occurred at the oxygen atom. On the other hand, when a metallicsalt of this invention, namely, the sodium salt of 2,6-di-tert-butylphenol, was employed, the benzoylation occurred not on the oxygen atomas would be expected, but occurred on the ring of the phenol. Thisfurther demonstrates the novel structure and characteristics of themetal salts of this invention and the novel reactions which theyundergo.

The unexpectedly altered course of the reaction using a metal salt ofthis invention as described in Example XV is encountered when reactingother metal salts of this invention with other acid halides. For examplepara-substituted 2,6-di-tert-alkyl phenols are formed when such salts asthe potassium salt of 2,6-di-tert-butylphenol, the sodium salt of2,6-di-(1,1,3,34etramethylbutyl) phenol and the lithium salt of2,6-di-tert-amyl phenol are reacted with such compounds as acetylbromide, propionyl chloride, crotonyl bromide and the like.

It will now be appreciated by those skilled in the art that by makingavailable the novel metallic salts of this invention novel chemicalreactions have now been made available for the first time. For example,the novel metallic salts of this invention readily undergo reaction withorganic halides such as propyl bromide, hexyl chloride, isopropylbromide, sec-butyl chloride, isobutyl iodide, benzyl chloride, allylbromide, etc.; acid halides such as acetyl chloride, propionyl bromide,crotonyl chloride, phosgene, benzoyl bromide, etc; inorganic halidessuch as phosphorus trichlo-ride, phosphoryl bromide, phosphorylchloride, sulfur dichloride, silicon tetrachloride, titaniumtetrachloride, manganous chloride, lead tetrachloride, etc.; acidanhydrides such as acetic anhydride, succinic anhydride, benzoicanhydride, etc.; cyclic oxides and sulfides such as ethylene oxide,1,2-propylene oxide, 1,2- butylene oxide, 2,3-butylene oxide, styreneoxide, 1,2-proepylene sulfide, ethylene sulfide, etc.; cyclic iminessuch as ethylene imine, N-phenyl-ethylene imine, 1,2-propylene imine,etc.; organic sulfate esters such as dimethyl sulfate, diethyl sulfate,etc.; organic phosphorus halides such as phenyl phosphorus dichloride,butyl phosphorus dibro- Inide, o,o-di-(xylyl) phosphoryl chloride,o,o,-di(p-tolyl) phosphoryl chloride, etc.; and the like.

The products readily prepared by employing the metal salts of thisinvention as chemical reactants or intermediates are useful in thechemical arts. For example, many of the compounds prepared from themetal salts of this invention are themselves particularly useful aschemical intermediates for antioxidants, germicidal preparations,wetting agents, and the like. Thus, the compounds prepared by reactionbetween metal salts of this invention and acrylonitrile possessing acyano group are readily susceptible of chemical reactions with Grignardreagents, reducing agents, or can be readily subjected to hydrolysisleading to novel and useful products. Particularly good antioxidants areprepared by reacting the metal salts of this invention with organichalides or with acid halides. The resulting products are very effectivein inhibiting the om'dative deterioration of gasoline, lubricating oil,tetraethyllead and other organometallic compounds, industrial oils,plastics, natural and synthetic rubber, high molecular weight polymers,greases, waxes, edible fats and oils and the like. Products derived fromthe salts of this invention which contain metal or metalloid elementssuch as silicon and titanium are readily adapted to use ascopolymerizing agents in the formulation of resins and other usefulpolymers. Other applications of the products derived from the metalsalts of this invention will now be apparent to those skilled in theart.

The outstanding utility of products made from the metal salts of thisinvention was illustrated by carrying out a series of standardantioxidant tests on gasoline. In one instance, an antioxidant-freegasoline having an induction period of minutes according to ASTM TestProcedure D525-46 (see Part IIIA, ASTM Standards for 1946) was treatedwith ,8-(3,5-di-tert-butyl-4-hydroxyphenyl) propionitrile so that theresultant fuel contained four milligrams of this compound permilliliters. When this finished gasoline was subjected to the above ASTMtest procedure, it 'was found that the induction period was over 250percent as long as the induction period of the same gasoline when devoidof the propionitrile. This test shows that when small amounts of 5- (3,5-di-tert-butyl 4 hydroxyphenyl) propionitrile are blended withgasolineswhich may be clear or leaded unusually great resistance againstoxidative deterioration is provided In the same manner, it has beenfound that small amounts-cg, less than one percent by weightof2,6-di-tert-butyl-4-benzoyl phenol-4n various gasolines likewise providesignificant protection against oxidative deterioration.

I claim:

1. Process for the preparation of B-(3,5-di-tert-butyl-4-hydroxyphenyl)propionitrile which comprises reacting the sodium salt of2,6-di-tert-butyl phenol with acrylonitrile.

2. fl-(3,5-di-tert-butyl-4-hydroxyphenyl)propionitrile.

3. Gasoline normally tending to undergo oxidative deterioration,containing, as an antioxidant, a small amount of the compound of claim2.

Hale May 15, 1956 Hoatson et a1. -2 May 14, 1957

1.
 2. B-(3,5-DI-TERT-BUTYL-4-HYDROXYPHENYL) PROPIONITRILE, 3.GASOLINENORMALLY TENDING TO UNDERGO OXIDATIVE DETERIORATION, CONTAINING, GAS ANANTIOXIDANT, A SMALL AMOUNT OF THE COMPOUND OF CLAIM 2.